Th Bones In My Upper Left Breast Seems To Have

Th bones in my upper left breast seems to have grown bigger than the ones on my right. It's like the bones below the collar bone and right on my upper breast.

I'm a 27 yr old woman and I've had minor breast surgery on my right breast months ago - incision biopsy but nothing serious really.

I used to work out (lasted for a few months) and I don't know if it has something to do with this.